The present invention relates generally to the field of circuit breakers and, more particularly, to a locking device for locking the circuit breaker handle in either an on or an off position.
It is frequently necessary to ensure that electrical equipment cannot be operated, for example while maintenance work is being carried out. It is essential to ensure that circuit breakers associated with the equipment are secured in the OFF position to avoid inadvertent operation that can lead to unplanned personnel exposure or equipment damage. Also, it is also often necessary to ensure that equipment is secured in the ON position, to prevent accidental shutdown of machinery, such as refrigeration equipment, life support systems, fire protection devices and continuous processes which require 1-2 days to start (e.g. cement manufacturing). Therefore, the ability to lock the circuit breaker in either the off or the on position is desirable. Further, when the circuit breaker is locked in the on position, an unintentional or purposeful trip of the circuit breaker caused by the pressing of a trip test button is undesirable. In such an instance, an electrical unit is needlessly shut down causing unnecessary time delays and costly down time.
In an exemplary embodiment of the invention, a locking device for use on a circuit breaker having a housing and an operating handle. The locking device comprising a yoke member fixedly attached to the housing, a slider member slidably engaged to the yoke member, a handle block depending from the slider member and positioned to abut the operating handle in an engaged position, and a first lock arranged to secure the slider member and the handle block in the engaged position. When the locking device is locked, the handle block abuts the operating handle in an engaged position corresponding to the operating handle in the ON or OFF position. Thus, the locking device locks the circuit breaker in the OFF position or the ON position. The locking device may further comprise a base member disposed between the yoke member and the housing. When it is desired to lock the circuit breaker in the on position, the base member is adapted to cover the push-to-trip button on the housing.